Date Système et Powershell

Depuis combien de temps l'odinateur est-il démarré ?

$os = Get-WmiObject -Class Win32_OperatingSystem
(get-date) - $os.ConvertToDateTime($os.LastBootUpTime)

http://msmvps.com/blogs/richardsiddaway/archive/2009/08/13/system-up-time.aspx

...et date de démarrage

$operatingSystem = Get-WmiObject Win32_OperatingSystem
[Management.ManagementDateTimeConverter]::ToDateTime($operatingSystem.LastBootUpTime)

http://blogs.msdn.com/powershell/archive/2009/08/12/get-systemuptime-and-working-with-the-wmi-date-format.aspx